Process of regenerating cellulose



Patented Sept. 4, 19:23..

ALBERT D. CONLEY AND ELTING C. STILLW'ELL, OF BALTIMORE, HARYLAND, .A S-SIGNOBS, BY MESNE ASSIGNMENTS, T JAMES P. EOOPER MANUFACTURJNG COM-PANY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

' rao'cass or nncnnnna'rme CELLULOSE.

N0 Drawing. Application filed May 6, 1919, SerialNo. 295,088. RenewedJune 12, 1923. v

Films or filaments as usually prepared from viscose, are more orless'harsh to the touch, lack the desired transparency and are subjectto a considerable degree of shrinkage during the drying operations.

The objects therefore of the present invention are to produce a film orfilament of a soft texture. more closely resembling that of naturalsilk; which film or filament, when in the form of a film, will possess ahigh deee of transparency, and in which the shrinkage during dryingwillbe materially lessened. i

The improvement consists in preparing, by any satisfactory method, filmsor filaments, and while wet, subjecting them to the 0 action of a bathconsisting of an alcohol.

This bath may be made acid With'five percent more or lessof acid withgood results but in practice we prefer to use a neutral bath. HCl andacetic acid may be mentioned as suitable acids. The filaments aresubjected to this bath for such time as is necessary to produce thedesired result but ordinarily a period of one minute has been found tobe sufiicient. In commercial op-.

eration, ordinary wood alcohol, denatured alcohol, preferably denaturedwith some material soluble in water, or refined fusel oil may be used.

We regard the novelty of the present invention as residin in thepreparation of films or filaments rom viscose in which the films orfilaments are subjected whilejin the wet condition to a bath consistingof an alcohol, or to a bath consisting of an alcohol containing fivepercent more or less of acid.

In: connection with this step We may use other steps or combinations ofsteps already known to the art" In order that our mode of operation maybe thoroughly understood we give the following example, but desire itunderstood that we do not limit our inven-- film or filament to aprecipitating bath of I hot saturated ammonium sulfate, and follow thisby a cleaning in hot sodium bisulfite. The film or filament is thenwashed in water and immersed while still wet in methyl alcohol asdescribed above. Following this the films or filaments are dried in asuitable manner.

What we claim is,- v

1. A process which comprises setting viscose in a hot solutioncontaining ammon um sulfate, nd thereafter, without an intermediatedrying, soaking in an alcoholic-liquid.

2. A process of improving regenerated cellulose articles comprisingformlng the article and setting the same, washing the article to, removesalts and while wet subject-- ing the article. to a bath of an alcoholicliquid.

3. A process which comprises settin a,

removing the product from the settin bath, treating the same with acleanlng bat and after removing the same from sald cleaning bath,subjecting the same to treatment with viscose solution in a settingbath, and ater In testimony whereof we aflix our signatures.

I ALBERT D. CONLEY.

ELTING C. STILLWELL.

